Isethionic acid also bears the chemical nomenclature of 2-hydroxy ethanesulfonic acid.
Heretofore, isethionic acid has been prepared by the hydrolysis of ethionic acid or carbyl sulfate, products which result from the reaction of two moles of sulfur trioxide with one mole of ethanol or ethylene, respectively. However, these preparations resulted in the formation of an equimolar amount of undesired sulfuric acid. Another approach proposed the reaction of a large excess of ethylene with sulfur trioxide to give an oligomer (C.sub.2 H.sub.4).sub.1.0 (SO.sub.3).sub.1.14 that can then be hydrolyzed to isethionic acid containing less sulfuric acid than the previous reaction.
It was also known to produce carboxylic acid esters of hydroxy-alkane-sulfo acids by mixing a carboxylic acid with a metal salt hydroxy-alkane-sulfo acid and passing gaseous hydrogen chloride through the mixture, as disclosed in U.S. Pat. No. 3,167,570, granted Jan. 26, 1965 to Bohanek, et al.
Zinc isethionate, for instance, was recognized as being useful as one of a number of metal salt catalysts in the preparation of acyl isethionates in Great Britain Patent No. 848,463, published Sept. 14, 1960, to Van Alphen, et al. Generally, metal saklt isethionates had been commercially prepared from ammonium isethionate as discussed in Chem Abstracts 67 63797r and Great Britain Pat. No. 1,059,984.
Now there is provided by the present invention an improved method of producing isethionic acid in a form which is readily converted into the corresponding polyvalent metal isethionate, which may be used as such, in solution, for numerous applications, for instance, as a catalyst.
It is therefore a principal object of the present invention to provide a novel method for the preparation of isethionic acid.
It is a further object of the present invention to provide a method as aforesaid wherein a heavy metal isethionate may be readily produced from the isethionic acid.
It is a further object of the present invention to provide a method as aforesaid in which by-product sulfuric acid is avoided in preparing the isethionic acid.
It is still a further object of the present invention to provide a method as aforesaid which the amount of water present is at a minimum.
It is still a further object of the present invention wherein the by-products of the isethionic acid reaction are readily removed.
It is still another object of the present invention to produce the heavy metal isethionate which is useful as a catalyst.
The aforesaid, as well as other objects and advantages, will become apparent from a reading of the following description, and the adjoined claims.